Poly(vinyl pyrrolidone) Mediated Solubilization and Stabilization of Fullerene C₆₀in the Form of Nanofluid in an Alcoholic Medium

Abstract

We report on the solubilization and stabilization of C 60 molecules in presence of a macroscopic capping agent such as poly(vinyl pyrrolidone) PVP polymer in n-butanol using a sonochemical route. Augmentation in the absorbance value by nearly two times in the p ® p* band in the C(sp 2 ) electron transitions of C 60 molecules at 328 nm in presence of PVP suggests an increase in the electron charge density on the surface interface via donor-acceptor interaction. A reasonably broad band feature observed in the p ® p* transition at 435 nm in PVP moieties in a PVP-surface modified C 60 sample indicates that PVP is cross-linking over the C 60 surface in specific structure. Quenching of light emission in PVP molecules in n-butanol results from non bonding electrons (n) transfer from C=O: (PVP) moieties to a C 60 nanosurface in a C 60 :PVP charge transfer (CT) complex. Dynamic light scattering band measures two bands one at 32.0 nm and other one at 8.1 nm with average values of hydrodynamic diameter 9.2 nm and polydispersity index 0.35 apparently in two types of distinct structures. The zeta plot in the 4.63 μM C 60 with PVP measures a zeta band with full width at half maximum ~14.4 mV with average values of Downloaded by [New York University] at 13:46 05 August 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 zetapotential x (-) 12.4 mV and surface conductivity of 0.074 mS/cm. The negative x-value describes that of O-atom of PVP molecules accumulate on the C 60 surface via a chemisorptions process. Raman and Fourier transform infrared bands show that CT complex made in n-butanolpresents a poor donation of the C=O n-electrons from PVP moiety to the C 60 molecules owing to adverse steric effect. High resolution transmission electron images in C 60 -PVP nanofluids illustrates a core-shell structure which consists of a C 60 core covered by a shell of nearly 2.0 nm thickness of an amorphous PVP layer of a whitish contrast.

Synthesis and characterization of gold (Au): Fullerene (C60)-Poly (vinyl pyrrolidone) nanofluids in an alcoholic medium

“…We studied absorption spectra ( Figure 1 A) in the 250-900 nm region in the NFs, which consists of (a) 0, (b) 1, (c) 2, (d) 3, (e) 5, (f) 10.0, (g) 30.0, and (h) 50.0 µM Au along with 10.0 µM C 60 in the presence of 40.0 g/L PVP in butanol. The optical absorption spectrum exhibits surface plasmon resonance (SPR) enhanced dipole allowed transition near 300 nm in C(sp 2 ) electrons when Au attached to C 60 /PVP (3)(4)(5)(6)(7)(8)(9)(10)18) .In the presence of Au, a characteristic Au-SPR band group exhibits over 500−900 nm with an average wavelength maxima λ max = 535 nm. FTIR results show that a non-covalent interaction occurs between Au and ">C=O" (PVP) sites.It can be seen from the spectra in Figure 1B that the Au brings a substantial change and red-shift in the PVP (>C=O) vibrational band.…”

“…Figure 2A shows the emission spectra in the 350-600 nm region in the NFs, which consists of (a) 0, (b) 1, (c) 2, (d) 3, (e) 5, (f) 10.0, (g) 30.0, and (h) 50.0 µM Au along with 10.0 µM C 60 in the presence of 40.0 g/L PVP in butanol. Spectra shows that a small doping of 1 µM Au decreases the light intensity of PVP band by nearly~30% as a consequence of energy transfer from PVP to Au-surface (2)(3)(4)(5)(6)(7)(8) . Doping of 50 µM Au almost vanish (~0%) the light emission from PVP.…”

“…C 60 NFs finds applications in various areas like photovoltaics, catalysis, sensors, biomedicals, etc. (1)(2)(3)(4)(5)(6)(7)(8) . Usually, four strategies were widely used in developing C 60 in aqueous or nonaqueous medium: (1) surface functionalization; (2) solvent exchange method;…”

“…(3) mechano-chemical method; and (4) surface modification method (2)(3)(4)(5)(6)(7)(8)(9)(10) . Since the last seven years, we are actively involved in developing C 60 NFs with and without gold NPs in aqueous and non-aqueous media using method-4 (2)(3)(4)(5)(6)(7)(8)(9)(10) . Owing to possession of excellent properties by C 60 and noble metal NPs like gold (Au), fullerene-gold NP combination is preferred to harvest the unique electron or energy transfer properties useful for photovoltaics, sensing and biomedicals that cannot be obtained either with individual metals or with C 60 in an efficient manner.…”

Irreversibility analysis through neural networking of the hybrid nanofluid for the solar collector optimization

“…(CSP) operate in the absence of sunlight and more efficiently in those areas where sunlight is not available at all times. The researchers observed through the experiments that the advanced nanomaterials are more prominent to improve the efficiency of the solar collector, heat exchangers based on the uniform particle distribution 1 – 3 , tools for the solubilization of the nanoparticles 4 , and optical absorption 5 , 6 . The optimization in the heat transfer is also a key factor in the energy sector and the researchers have used their efforts to predict the suitable materials for the enhancement of heat transfer.…”